Heartworm Disease in Dogs

Heartworm disease is a serious and potentially fatal disease in pets. It is caused by foot-long worms (heartworms) that live in the heart, lungs and associated blood vessels of affected pets, causing severe lung disease and heart failure and damage. Heartworm disease affects both dogs and cats.

If a dog has heartworms, what symptoms should I look for?

In the early stages of the disease, your pet may show no signs at all. The longer the infection persists, the more likely the symptoms will develop. Dogs heavily infected with heartworms will show a mild persistent cough, exercise intolerance, decreased appetite, and weight loss. As heartworm disease progresses, pets may develop heart failure with the appearance of a swollen belly due to excess fluid in the abdomen. Dogs with large numbers of heartworms can develop sudden blockages of blood flow within the heart, leading to a life-threatening form of cardiovascular collapse. It is called Caval syndrome and is marked by a sudden onset of laboured breathing, pale gums, and dark bloody or coffee-coloured urine. Without prompt surgical removal of the heartworm blockage, few dogs survive.

How does a dog get heartworms?

A dog can get infected with heartworms by the bite of an infected mosquito. There’s no other way dogs get heartworms, and there’s no way to tell if a mosquito is infected. That’s why prevention is so important.

What are the treatment options for heartworms?

Once your dog has a confirmed heartworm infection and is ready for heartworm treatment, our veterinarians will recommend a treatment protocol involving several steps. At Westwood Veterinary Hospital, we follow the guidelines and treatment protocols recommended by the American Heartworm Society. Please call us at 204.489.9111 for more information.

Why is recovery for heartworm treatment so challenging?

During treatment and recovery, your dog’s activity has to be restricted, which may be challenging. Your dog’s normal physical activities must be restricted as soon as the diagnosis is confirmed because physical exertion increases the rate at which the heartworms cause damage to the heart and lungs.

Last updated: Sep 16, 2022

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